BR112020010426A2 - slit tool body, rotary slit cutting tool and cutting insert - Google Patents

Abstract

A slit tool body (22) includes a disc-type cutter portion (26) and a shank portion (56) projecting backward from it. The cutter portion (26) includes a resilient clamping portion (32) having an insert receiving slot (38) peripherally arranged. The shank portion (56) includes a peripherally disposed front shank (60) that is axially adjacent to the cutter portion (26). A radially inward portion of the insert receiving slot (38) merges in the backward direction with the front stem indentation (60). A cutting insert (24) is releasably and resiliently attached to the insert receiving slot (38) to form a rotary slot cutting tool (20). The cutting insert (24) includes two cutting portions (94a, 94b), each including a long and short side insert extension (98a, 98b), the long insert side extension (98a) being longer than the lateral extension of short insert (98b). The longest lateral insert extensions (98a) are located on opposite sides of the cutting insert (24).

Description

CRACKING TOOL BODY, CUTTING TOOL OF ROTATING SLIT AND CUTTING INSERT FIELD OF THE INVENTION

[001] The subject matter of the present application relates to rotary slit cutting tools having a slit tool body with a disk-type cutter portion having a plurality of insert receiving pockets circumferentially arranged to releasably retain a cutting insert thereon, in general, and for such slit tool bodies in which the insert receiving pocket resiliently holds the cutting insert therein in particular.

BACKGROUND OF THE INVENTION

[002] Rotary slit cutting tools may have a slit tool body that has a disk-type cutter portion and a shank portion that extends perpendicularly to the disk-type cutter portion. The disk-type cutter portion can be provided with a plurality of insert receiving pockets circumferentially arranged to retain a cutting insert therein. The cutting insert can be retained in the insert receiving pocket by a retaining screw. Examples of such rotary cutting tools are disclosed in, for example, US 6,571,451 and US 8,834,075.

[003] In other rotary slit cutting tools, the cutting insert can be retained in the insert receiving pocket by a resilient fastening member. Examples of such rotary cutting tools are disclosed in, for example, US 6,116,823 and US 8,708,610, where the cutting inserts are single-ended. Alternatively, the cutting insert can also be double-ended, as shown in US 5,059,068.

[004] In still other rotary slit cutting tools, in particular for internal grooving in small holes, it may be preferable to use disk-shaped solid carbide slit heads with a plurality of cutting edges. Examples of such rotary cutting tools are disclosed in, for example, US 6,276,879 and US 8,708,611. However, such slit heads are relatively expensive to manufacture and if one of the cutting edges is damaged, the entire slit head needs to be replaced.

SUMMARY OF THE INVENTION

[005] According to a first aspect of the subject matter of the present application, a slit tool body is provided, having a central axis of the body that defines opposite directions back and forth and on which the slit tool body is rotatable in a rotational direction, the slotting tool body comprising: a disk-type cutter portion comprising a resilient gripping portion having a peripherally arranged insert receiving slot; and a shank portion projecting backwardly from the cutter portion, the shank portion comprising a peripheral shank surface which extends circumferentially over the central axis of the body and a front shank indentation recessed in and opened outwardly to the peripheral surface of the rod adjacent to the cutter portion; where: a portion radially into the insert receiving slot merges in the backward direction with the front stem indentation.

[006] According to a second aspect of the subject matter of the present application, a rotary slit cutting tool is provided comprising: a slit tool body of the type described above; and a cutting insert, loosely and resiliently attached to the insert receiving slot.

[007] According to a third aspect of the subject matter of the present application, a cutting insert is provided, longitudinally elongated in a direction that defines a longitudinal axis of the insert, comprising:

upper and lower surfaces of opposite inserts and a peripheral insert surface extending between them, the peripheral insert surface comprising two opposite insert end surfaces connecting the upper and lower insert surfaces and two opposite insert lateral surfaces which also connect the upper and lower insert surfaces;

a longitudinal insert plane containing the longitudinal insert axis, passing between the lateral insert surfaces and intersecting the upper and lower insert surfaces and also intersecting the opposite insert end surfaces; and two cutting portions located at opposite ends of the cutting insert, each comprising a cutting edge formed at the intersection of the upper insert surface and one of the two insert end surfaces; on what:

each insert cutting portion comprises two lateral insert extensions which project laterally from opposite sides of the cutting insert in a direction away from the longitudinal plane of the insert and over which the cutting edge extends;

the two lateral insertion extensions comprise a wide and narrow lateral extension extension, the wide lateral extension extension being longer than the narrow lateral extension extension in a direction perpendicular to the longitudinal insert plane; and the wide lateral insert extensions are located on opposite sides of the longitudinal plane of the insert.

[008] According to a fourth aspect of the subject matter of the present application, a slit tool body is provided, having a central axis of the body that defines opposite directions back and forth and on which the slit tool body is rotatable in a rotational direction, the slotting tool body comprising: a disk-type cutter portion comprising a resilient gripping portion having a peripherally arranged insert receiving slot; and a shank portion projecting backwardly from the cutter portion, the shank portion comprising a peripheral shank surface which extends circumferentially over the central axis of the body and a front shank indentation recessed in and opened outwardly to the peripheral surface of the rod adjacent to the cutter portion; wherein: in a front view of the slit tool body, in a direction along the central axis of the body, the shank portion is partially visible through the insert receiving slot.

[009] It is understood that the aforementioned is a summary and that the features described hereinafter may be applicable in any combination to the subject of this application, for example, any of the following features may be applicable to the slit tool body and the rotary slit cutting tool and cutting insert:

[010] The cutter portion and the shank portion are integrally formed so that the slit tool body has a unitary, one-piece construction.

[011] The clamping portion may additionally comprise a resilient clamping member and a lower jaw member that are opposed to each other and are spaced from each other by the insert receiving slot, the resilient clamping member being rotatably arranged in front of the lower clamping member and configured to resiliently retain a cutting insert in the insert receiving slot.

[012] The resilient fastening member can be axially adjacent to the front stem indentation.

[013] The shank portion can comprise a peripherally disposed front shank portion that can be circumferentially adjacent to the front shank indentation and axially adjacent the cutter portion.

[014] The cutter portion may further comprise at least one additional resilient clamping portion to form a plurality of clamping portions that are angularly spaced from one another. The stem portion may further comprise at least one additional front stem indentation to form a plurality of front stem indentations that are angularly spaced from each other. The stem portion may further comprise at least one additional non-recessed front stem portion to form a plurality of non-recessed front stem portions that are angularly spaced from each other, each non-recessed front stem portion being located between two stem indentations. circumferentially adjacent front. A radially inward portion of each insert receiving slot may merge in the rear direction a respective front stem indentation.

[015] In a direction along the central axis of the body; an imaginary radius line that extends between the central axis of the body and a more distant portion in the non-indented front stem portion defines a stem portion radius of a stem portion circle that is centered on the central axis of the body and that has a stem portion diameter; and the cutter portion defines a circumscribed cutter portion circle which is centered on the central axis of the body and which has a cutter portion diameter.

[016] In a direction along the central axis of the body, the stem portion circle can intersect the insert receiving slot.

[017] Insert receiving groove can be defined by an elongated slit peripheral surface comprising a lower jaw support surface located in the lower jaw member. In a direction along the central axis of the body, the stem portion circle intersects the lower jaw support surface of the slot.

[018] The peripheral slit surface may further comprise a slit fastening member support surface located on the resilient fastening member. In a direction along the central axis of the body, the slit-holding member support surface may be located radially outside the stem portion circle.

[019] The peripheral slit surface may further comprise a radial slit stop surface located circumferentially between the slit fastening member support surface and the slit lower jaw support surface. In a direction along the central axis of the body, the radial slot stop surface may be located radially within the stem portion circle.

[020] The front stem indentation may further comprise an external recess gap arranged peripherally defined by an external indenting base surface facing forward and an external peripheral indentation surface extending transversely thereto, the external base surface recess and each end of the outer peripheral recess surface that intersects the peripheral stem surface.

[021] The front stem indentation may comprise an internal indentation gap defined by an internal indented base surface facing forward and an internal peripheral indentation surface extending transversely thereto. The internal recessed base surface can intersect the external peripheral recessed surface. Each end of the internal peripheral recoil surface can intersect the external peripheral recoil surface.

[022] The external indentation gap can be formed by a circumferential groove that extends in the circumferential direction.

[023] In a direction along the central axis of the body, the outer peripheral recoil surface can be concave curved and defined by an external peripheral recoil radius.

[024] In a side view of the slit tool body, the external peripheral recoil surface can be concavely curved and defined by a peripheral lateral radius.

[025] The cutting insert can be longitudinally elongated in a direction that defines a longitudinal axis of the insert, the cutting insert can comprise: upper and lower surfaces of opposite inserts and a peripheral insert surface extending between them, the surface peripheral insert comprising two opposite insert end surfaces connecting the upper and lower insert surfaces and two opposite insert lateral surfaces which also connect the upper and lower insert surfaces; a longitudinal insert plane containing the longitudinal insert axis, passing between the lateral insert surfaces and intersecting the upper and lower insert surfaces and also intersecting the opposite insert end surfaces; and

[026] a cutting portion located at one end of the cutting insert, the cutting portion comprising a cutting edge formed at the intersection of the top insert surface and one of the two insert end surfaces, where:

[027] the insert end surface opposite the cutting portion comprises an indented insert portion comprising an insert wrench surface which is closer to the lower insert surface than to the upper insert surface, the insert wrench surface being configured for support by a key displacement pin used to extract the cutting insert from the insert receiving slot.

[028] In a side view of the cutting insert, the insert wrench surface can be concavely curved.

[029] The insert key surface may be located entirely below a median plane of the insert that extends halfway between the upper and lower insert surfaces and contains the longitudinal insert axis.

[030] The insert end surface opposite the cutting portion may further comprise an insert stop surface which may be closer to the upper insert surface than the lower insert surface, the insert stop surface being flat .

[031] The cutting insert may comprise an additional cutting portion forming two cutting portions, the two cutting portions being formed at the opposite ends of the cutting insert.

[032] Each insert cutting portion may comprise two lateral extensions of the insert which project laterally from opposite sides of the cutting insert in a direction away from the longitudinal plane of the insert and over which the cutting edge extends . The two lateral insert extensions can comprise a wide and a narrow insert lateral extension, the wide insert lateral extension being longer than the narrow insert lateral extension in a direction perpendicular to the longitudinal insert plane. The wide lateral insert extensions can be located on opposite sides of the longitudinal plane of the insert.

[033] The two cutting portions may comprise an active cutting portion and a non-active cutting portion, the cutting edge of the active cutting portion being located beyond the radial extension of the cutter portion. The wide insert lateral extension of the active cutting portion can be the axially ahead of the two insert lateral extensions with respect to the axial direction.

[034] The insert receiving slot may comprise a slot insert portion defined by a cutting insert insert profile in a direction along the central axis of the body. A portion radially inward of the slit insert portion may merge in the backward direction with the front stem indentation.

BRIEF DESCRIPTION OF THE FIGURES

[035] For a better understanding of the subject of this application and to show how it can be done in practice, reference will now be made to the attached drawings, in which:

[036] Fig.1is a front perspective view of a rotary slot cutting tool, with a cutting insert resiliently attached to an insert receiving slot, according to the present order;

[037] Fig.2 is an exploded rear perspective view of the rotary slit cutting tool shown in Fig. 1;

[038] Fig. 3 is a front view of a slit tool body in Fig. 1;

[039] Fig. 4 is a side view of the slit tool body shown in Fig. 3;

[040] Fig.5 is a side view of a fastening portion in Fig. 3, with an overlapping insert profile;

[041] Fig.6 is a front view of the fastening portion in Fig. 5, taken along the “VI” direction line;

[042] Fig.7 is a perspective view of a cutting insert, according to the present application;

[043] Fig.8 is a side view of the cutting insert shown in Fig. 7;

[044] Fig.9 is a top view of the cutting insert shown in Figs. 7 and 8 and

[045] Fig.10 is a view similar to that shown in Fig. 1, prior to extracting the cutting insert from the insert receiving slot with a key.

[046] It will be appreciated that for simplicity and clarity of illustration, the elements shown in the figures were not necessarily drawn to scale. For example, the dimensions of some of the elements can be exaggerated in relation to other elements for clarity, or several physical components can be included in a block or functional element. In addition, where deemed appropriate, reference numbers may be repeated between the figures to indicate corresponding or similar elements.

DETAILED DESCRIPTION OF THE INVENTION

[047] In the description that follows, various aspects of the subject matter of this application will be described. For purposes of explanation, specific settings and details are set out in sufficient detail to provide a complete understanding of the subject of this application. However, it will also be apparent to a person skilled in the art that the subject of this application can be practiced without the specific settings and details presented here.

[048] Attention is drawn first to Figs. 1 and 2, showing a rotary slit cutting tool 20, depicting an aspect of the present application, having a central tool axis A, suitable for slit cutting operations. The rotary slit cutting tool 20 can exhibit rotational symmetry about the central tool axis A. The rotary slit cutting tool 20 has a slit tool body 22 which can typically be made of steel. The rotary slit cutting tool 20 has a cutting insert 24 which can typically be made of cemented carbide. The cutting insert 24 is releasably attached to the slit tool body 22.

[049] Note that the term "rotary slit cutting tool" as used in the present invention can be replaced by other terms applicable in the metal cutting field for such cutting tools, for example, "slit cutter", "slot milling cutter", "slot milling cutter", "slot milling cutter", "slot milling cutter", "slot milling cutter", "side milling cutter", "disc milling cutter" and the like.

[050] Now reference is also made to Figs. 3 and 4, showing another aspect of the subject matter of the present application, related to the slit tool body 22. The slit tool body 22 has a central axis of body B which is co-incident with the central tool axis A. central axis of body B defines opposite directions forwards and backwards Dr, Dr. The central axis of body B forms a axis of rotation about which the slotting tool body 22 is rotatable in a rotational direction R.

[051] It should be appreciated that the use of the terms "front" and "rear" throughout the description and claims refers to a relative position in the direction of the central axis of the body B downwards and upwards, respectively, in Fig. 4. In addition, the terms “axial” and “radial” are with respect to the central tool axis B, unless otherwise specified.

[052] As shown in Fig. 3, the slit tool body 22 includes a disk-type cutter portion 26. The cutter portion 26 includes two opposite cutter portion side surfaces 28 and a cutter portion peripheral surface 30 extending between the side surfaces of cutter portion 28. The peripheral surface of cutter portion 30 extends circumferentially over the central axis of body B. The central axis of body B intersects the two side surfaces of cutter portion 28 in one central portion of it. In a front view of the slotting tool body 22, in a direction along the central axis of the body B (i.e., Fig. 3), the cutter portion 26 defines a circumscribed cutter portion circle CC that is centered on the central axis of body B and which has a DC cutter portion diameter.

[053] As shown in Fig. 4, in the axial direction, measured between the two side surfaces of cutter portion 28, cutter portion 26 has a cutter portion width WC. According to some embodiments of the subject matter of the present application, the two side surfaces of cutter portion 28 may be flat and perpendicular to the central axis of body B. The cutter portion 26 may include a pivot pin hole 31 for receiving a pin pivot 51b of a key 52 when detaching the cutting insert 24 from the cutter portion 26, as discussed later in the description.

[054] The cutter portion 26 includes a clamping portion 32. According to some embodiments of the subject matter of the present application, the cutter portion

26 may further include at least one additional clamping portion 32 to form a plurality of clamping portions 32 that are angularly spaced from each other. It is understood in the description below that any resource related to a single clamping portion 32 can also be related to the other clamping portions 32 if present. The plurality of fastening portions 32 can be arranged in the same axial position along the central axis of the body B in the front to back direction. Each clamping portion 32 may have a chip throat 33 on the cutter portion peripheral surface 30, so that the cutter portion 26 may not be completely circular in a front view.

[055] The clamping portion 32 includes a resilient clamping member 34 and a lower jaw member 36 which are opposed to each other and spaced from each other by an insert receiving slot 38. That is, the insert receiving slot 38 is formed between the resilient fastening member 34 and the lower jaw member 36. The insert receiving slot 38 extends along an insert receiving slot axis C, so that in a front view of the slotting tool body 22, the resilient clamping member 34 and the lower jaw 36 are located on opposite sides of the insert receiving slit shaft C. The resilient clamping member 34 is rotatably arranged in front of the lower jaw member 36 and the insert receiving slit 38. The resilient fastening member 34 is configured to resiliently retain the cutting insert 24 in the insert receiving slot 38. The resilient fastening member 34 is resiliently displaceable relative to the member the lower jaw 36. In other words, the holding portion 32 is resilient. Note that the securing portion 32 is devoid of a resilient slit rotatably forward of the resilient securing member 34 as disclosed in US 6,116,823 and US

8,388,270.

[056] Reference is also made to Fig. 5, showing a side view of the holding portion 32, (that is, perpendicular to the insert receiving slot axis C), the insert receiving slot 38 opens to the peripheral surface of the cutter portion 30. Thus, the insert receiving slot 38 is arranged peripherally. Reverting to Fig. 4, the insert receiving slot 38 opens laterally on both sides to the side surfaces of cutter portion 28. The context of "laterally" in reference to the insert receiving slot 38 means perpendicular to the insert receiving slit axis C and therefore generally in a direction parallel to the central axis of body B.

[057] The insert receiving slot 38 is defined by an elongated peripheral slot surface 40 having ends that extend to the cutter portion peripheral surface 30. The peripheral slot surface 40 extends between the two lateral portion portion surfaces. cutter 28. The peripheral slit surface 40 includes a slit clamping member support surface 42 located on the resilient clamping member 34 to support a corresponding surface on the cutting insert 24. The slit peripheral surface 40 includes a sliding support surface slit lower jaw 44 located on the lower jaw member 36, to confine a corresponding surface on the cutting insert 24. The peripheral slit surface 40 includes a radial slit stop surface 46, for positioning the cutting insert 24 in a radial position exact predetermined. The radial slit stop surface 46 faces outwardly. According to some embodiments of the subject matter of the present application, the radial slit stop surface 46 can be located circumferentially between the slit fastening member support surface 42 and the slit lower jaw support surface 44.

[058] Referring to Fig. 5, the insert receiving slot 38 includes a slot insert portion 48 defined by an IP insert profile of the cutting insert 24 in a direction along the central axis of body B when releasably and resiliently secured to the insert receiving slot 38. The insert receiving slot 38 includes a screwdriver portion 50 extending radially inward from the insert receiving slot 38. A purpose of the key portion 50 is to act as a strain relief groove (as is known in the art). However, the screwdriver portion 50 is larger than the normal strain relief slots so it can also serve to receive a displacement pin 51a from the key 52 when extracting the cutting insert 24 from the receiving slot of insert 38. In addition, the screwdriver portion 50 is still rotatably forward than would normally be required if its purpose were only as a strain relief groove. For example, most of the insert wrench portion 50 is located above an extension of the lower jaw support surface 44. This allows the displacement pin 51a to be able to support one end of the cutting insert 24, while is located in the screwdriver portion

50. The insert receiving slot 38 includes a slot resilience portion 54, to provide the desired resilience to the resilient fastening member 34. The slot resilience portion 54 is located pivotally forward from the screwdriver portion 50 .

[059] Referring to Figs. 2 and 4, the slotting tool body 22 includes a shank portion 56 projecting from the rear most of the side surface of the cutter portion 28. That is, the shank portion 56 projects backwards from the portion of cutter 26. The stem portion 56 includes a peripheral stem surface 58 which extends circumferentially over the central axis of body B. According to some embodiments of the subject matter of the present application, the stem portion 56 may be integrally formed with the cutter portion 26 so that the slit tool body 22 has a unitary, one-piece construction, that is, the shank portion 56 and the cutter portion 26 are formed (for example, machined) from a single continuous piece of material. The stem portion 56 may have a basic cylindrical shape. As seen in Fig. 4, the peripheral shank surface 58 can intersect the side surface of cutter 28 on a shank fillet surface 59 that has a concave curvature. Said concave curvature may have an RF rod fillet radius that is greater than or equal to 1 mm and less than or equal to 2 mm.

[060] Reverting to Figs. 4 and 6, the stem portion 56 includes a front stem indentation 60 that is indented and opens outwardly to the peripheral stem surface 58. That is, the front stem indentation 60 is arranged peripherally and with radial indentation on the surface peripheral stem 58 near the front end thereof. The front stem indentation 60 is axially adjacent to the cutter portion 26. According to some embodiments of the subject of the present application, the stem portion 56 may further include at least one additional front stem indentation 60 to form a plurality of indentations from front rod 60 which are angularly spaced from each other. It is understood in the following description that any feature related to a single front stem indentation 60 can also be related to the other front stem indentations 60 if present.

[061] According to some embodiments of the subject matter of the present application, the stem portion 56 may include a non-recessed front stem portion 62 formed by a portion of the peripheral stem surface 58 that is not recessed. Like the front stem indentation 60, the non-receding front stem portion 62 is arranged peripherally. The non-recessed front stem portion 62 may be circumferentially adjacent to the front stem indentation 60 and axially adjacent to the cutter portion 26. Thus, the front stem indentation 60 may not extend around the entire circumferential length of the stem portion 56 (that is, it may not have a 360º angular extension). Similar to the front stem indentation 60, according to some embodiments of the subject matter of the present application, the stem portion 56 may further include at least an additional non-indented front stem portion 62 to form a plurality of non-stem front portions indented 62 which are angularly spaced from each other. The number of non-indented front stem portions 62 can match the number of front stem indentations 60. Each non-indented front stem portion 62 can be located between two circumferentially adjacent front stem indentations 60. That is, the stem indentation front 60 and the non-recessed front stem portion 62 can alternate in a circumferential direction. It is understood in the aforementioned description that any feature related to a single portion of the non-receding front stem 62 is also related to the other non-receding front stem portions 62 if present.

[062] As seen in Fig. 3, in a direction along the central axis of body B, a line of imaginary radius extending between the central axis of body B and a more distant portion in the non-receding front stem portion 62 defines a stem portion radius RS of a stem portion circle CS that is centered on the central axis of body B and that has a stem portion diameter DS. In the configuration with the plurality of non-receding front stem portions 62, the stem portion circle CS is a circumscribed circle defined by the plurality of non-receding front stem portions 62. Note that if the peripheral stem surface 58 has a thread, as described above, the stem portion diameter DS may be different (e.g., larger) than the diameter of a circumscribed circle (not shown) defined by the stem portion 56 taken in an increased rear axial position.

[063] According to some embodiments of the subject matter of the present application, the resilient fastening member 34 can be axially adjacent to the front stem indentation 60. That is, the free end of the resilient fastening member 34 is not connected to any part of the shank 56. As seen in Fig. 2, a rearwardly facing surface 34a of the clamping member 34 is facing the front stem indentation 60. In the front stem indentation 60, the resilient clamping member 34 is anchored circumferentially in a direction opposite to the direction of rotation R, with respect to a front shank portion not rotationally retracted forward 62. Advantageously, this allows the resilient clamping member 34 to bend slightly when cutting insert 24 meets the workpiece (along with the clamping member the lower insert 36 and the cutting insert 24) in order to maintain a firm clamping force on the cutting insert 24. A portion radially into the lower jaw 36 can be formed connected to the non-recessed front stem portion 62.

[064] Referring back to Fig. 5, according to some embodiments of the subject matter of the present application, the front stem indentation 60 may include an external indentation gap 64 which is defined by an external recessed base surface facing the front 66 and an outer peripheral recoil surface 68 that extends transversely to the outer recoil base surface 66. The outer recoil base surface 66 and each end of the outer recoil peripheral surface 68 can intersect the peripheral stem surface

58. Thus, the external indentation gap 64 is arranged peripherally. The ends of the outer peripheral recess surface 68 intersect with the peripheral stem surface 58 at two peripheral intersections 72 that subtend an outer recess gap angle 5 (shown in Fig. 3) on the central axis of body B. The gap angle external recoil 5 can be in the range of 60º <6 <80º. The external recess gap 64 can be formed by a circumferential groove that extends in the circumferential direction. In a direction along the central axis of the body B, the external peripheral recoil surface 68 can be concave curved and defined by an external peripheral radius of recoil RO. In a side view of the slotting tool body 22 (perpendicular to the central axis of the body B), the external peripheral recess surface 68 can be concave curved and can be defined by a peripheral lateral radius RS. As seen in Fig. 6, showing a front view of the gripping portion 32 along the insert receiving slit axis C, in the axial direction, the external recess gap 64 has an external recess gap width WO, measured between the cutter portion 26 and the external base recoil surface 66. The width of the external recoil gap WO can generally be twice the peripheral lateral radius RS.

[065] According to some embodiments of the subject matter of the present application, the front stem indentation 60 may include an internal indentation gap 74 which is defined by an internal forward recessed base surface 76 and an internal peripheral surface of indentation 78 extending transversely to the internal indentation base surface 76. The internal indentation base surface 76 can intersect the external peripheral recess surface 68. Each end of the internal peripheral indentation surface 78 can intersect the external peripheral recess surface 68. Generally speaking, the internal indentation gap 74 is radially inward from the external indentation gap 64. The peripheral slot surface 40 in the screwdriver portion 50 and the slot resilience portion 54 can each transition uniformly and continuously on the internal peripheral recoil surface 78. Likewise, the radial slit stop surface 46 can make the transition smooth and cont in the inner peripheral recess surface 78. Thus, in a direction along the central axis of body B, the peripheral slot surface 40 in the screwdriver portion 50 and the slot resilience portion 54 and the radial stop surface slot 46 can be aligned with the internal peripheral recess surface 78. As seen in Fig. 6, in the axial direction, the internal recess gap 74 has an internal recess gap width WI, measured between the cutter portion 26 and the internal base surface of indentation 76.

[066] According to some modalities of the subject of the present application, the width of the external recoil gap WO can be greater than or equal to 1 mm and less than or equal to 2 mm (1 mm <WO <2 mm). The width of the internal indentation gap WI may be less than the width of the external indentation gap WO (WI <WO). That is, the internal indentation gap 74 may be narrower than the external indentation gap 64 in the axial direction. The width of the external recoil gap WO may be less than the width of the WC cutter portion (WO <WC). That is, the external recess gap 64 may be narrower than the cutter portion 26 in the axial direction.

[067] A portion radially inward of the insert receiving slot 38 melts laterally on one side (i.e., the side of the insert receiving slot 38 that opens to the rear of the two side cutter portion surfaces 28 , that is, in the backward direction Dr) with the front stem indentation 60. Thus, the insert receiving slot 38 is deflected inwardly. Clearly, in the configuration with the plurality of fastening portions 32 and plurality of front shank indentations 60, the portion radially into each insert receiving slot 38 merges in the backward direction Dk with a respective front shank indentation 60. In a front view of the slotting tool body 22, in a direction along the central axis of the body B, the shank portion 56 is partially visible. More specifically, the stem portion 56 is partially visible through the slot insert portion 48. Thus, when the cutting insert 24 is releasably and resiliently attached to the insert receiving slot 38, the front stem indentation 60 is partially hidden.

[068] According to some embodiments of the subject matter of the present application, in a direction along the central axis of body B, the circle of the stem portion CS may intersect the insert receiving slot 38. In particular, the portion circle of stem CS can intersect the slot insert portion 48. Thus, a portion radially inward of the slot insert portion 48 can merge in the backward direction Dg with the front stem indentation 60. In addition, in particular, the stem portion circle CS may intersect the support surface of the lower slit jaw 44. The slit member support surface 42 can be located radially outside the stem portion circle CS. The radial slit stop surface 46 can be located radially within the stem portion circle CS. The screwdriver and resilience portions 50, 54 can be located radially within the stem portion circle CS.

[069] Referring to Figs. 2 and 6, according to some embodiments of the subject matter of the present application, the stem portion 56 may include a stem cooling channel 80 that opens to the stem peripheral surface 58 at the outlet of the cooling channel 82. The outlet of the stem cooling channel 82 can intersect the front stem indentation 60.

[070] Reference is now made to Figs. 7 to 9, showing another aspect of the subject matter of the present application, related to the cutting insert 24. The cutting insert 24 is longitudinally elongated in a direction that defines a longitudinal axis of the insert A. The cutting insert 24 includes top and bottom surfaces opposite insert inserts 84, 86 and a peripheral insert surface 88 extending between them. The upper and lower insert surfaces 84, 86 include upper and lower insert support surfaces 84a, 86a, respectively, for support with corresponding surfaces in the insert receiving slot 38. According to some embodiments of the subject matter of the present application, the lower insert surface 86 may contain an imaginary linear insert line L parallel to the longitudinal axis of insert A. The upper and / or lower insert support surfaces 84a, 86a may have a prismatic shape that matches a shape of the surface of insertion slit fastening member support 42 and / or slit lower jaw support surface 44, respectively, in order to avoid displacement of the cutting insert 24 in the lateral direction of the cutting insert 24.

[071] The peripheral insert surface 88 includes two surfaces of opposite insert ends 90 that connect the upper and lower insert surfaces 84, 86. The peripheral insert surface 88 includes two opposite insert lateral surfaces 92 that connect the upper surfaces and lower insert 84, 86. The longitudinal insert A axis intersects the insert end surfaces 90 and extends between the lateral insert surfaces 92 (Fig. 9) and also extends between the upper and lower insert surfaces 84 , 86 (Fig. 8). A lateral insert axis E extends perpendicularly to the longitudinal insert axis A halfway between the insert end surfaces 90 and intersects the two lateral insert surfaces 92, defining a lateral insert direction of the cutting insert 24.

A central insert axis F extends perpendicularly to the longitudinal axis of insert A midway between the end surfaces of the insert 90 and intersects the top and bottom surfaces of the insert 84, 86. A medium insert plane M contains the longitudinal axis of the insert insert A and the lateral insert axis E.

[072] As seen in Fig. 9, the longitudinal axis of insert A rests on a longitudinal plane of insert P1 that contains the central axis of insert F, passes halfway between the lateral surface of insert 92 and intersects both surfaces of end 90. A central plane of insert P2 perpendicular to the longitudinal plane of insert P1 and also to the longitudinal axis of insert A, contains the central axis of insert F and the lateral axis of insert E. According to some modalities of the subject matter of the present application , the cutting insert 24 may have 180 ° rotational symmetry about the central axis of insert F. Cutting insert 24 may not be a symmetrical mirror over the central plane of insert P2 or the longitudinal plane of insert P1.

[073] The cutting insert 24 includes a cutting portion 94a located at one end of the cutting insert 24. According to some embodiments of the subject matter of the present application, the cutting insert 24 may further include an additional cutting portion 94b for forming two cutting portions 94a, 94b, an active and a non-active cutting portion 94a, 94b. The two cutting portions 94a, 94b are located at opposite ends of the cutting insert 24. In other words, the cutting insert 24 is double-ended and can be indexed by rotating 180 * over the central axis of the insert F (ie (ie, the active cutting portion 94a becomes the non-active cutting portion 94b and vice versa). The two cutting portions 94a, 94b can be identical. It is understood in the description below that any feature related to a single cutting portion 94a can also be related to the other cutting portions 94b if present.

[074] The cutting portion 94a includes a cutting edge 96 formed at the intersection of the upper insert surface 84 and one of the two insert end surfaces 90. A portion of the insert end surface 90 adjacent to the cutting edge 96 serves as a relief surface. Likewise, an upper insert surface portion 84 adjacent to the cutting edge 96 serves as an inclined surface. When the cutting insert 24 is releasably and resiliently attached to the insert receiving slot 38, the cutting edge 96 of the active cutting portion 94a is located beyond the radial projection of the cutting portion 26 (i.e., beyond the circle of circumscribed cutter portion CC). Preferably, such a radial projection is not more than 1 mm. As seen in Fig. 9, the longitudinal plane of longitudinal P1 intersects the cutting edge 96, that is, the cutting edge 96 extends on both sides of the longitudinal plane of insert P1.

[075] Each lateral insert surface 92 protrudes out into the cutting portion 94a. That is, the cutting portion 94a includes two lateral insert extensions 98a, 98b that project laterally in a direction away from the longitudinal plane of insert P1 (i.e., perpendicular to the longitudinal plane of insert P1), on opposite sides of the insert of cut 24. The cut edge 96 extends to the two lateral insert extensions 98a, 98b. According to some embodiments of the subject matter of the present application, the two lateral insert extensions 98a, 98b can include a wide insert lateral extension 98a and a narrow insert lateral extension 98b, the width being measured in a direction perpendicular to the longitudinal plane of insert P1. As seen in the top view of the cutting insert 24 (i.e., Fig. 9), measured in the lateral direction with respect to a non-protruding portion of the lateral insert surface 92, the wide insert lateral extension 98a has a wide extension width WW and the narrow insert side extension 98b has a narrow extension width

WN, where the wide extension width WW can be greater than the narrow extension width WN. Thus, the wide insert lateral extension 98a is longer than the narrow insert lateral extension 98b in the lateral insert direction, i.e., in the direction perpendicular to the longitudinal plane of insert P1. Thus, the wide and narrow lateral insert extensions 98a, 98b are not identical. The wide insert lateral extension 98a may be longer than the narrow insert lateral extension 98b by between 1 mm and 2 mm, in the direction perpendicular to the longitudinal plane of insert P1. When there are two cutting portions 94a, 94b at opposite ends 90 of the cutting insert 24, the wide side extension of the insert 98a can be located on opposite sides of the longitudinal plane of insert P1. As seen in Fig. 1, the wide insert lateral extension 98a of the active cutting portion 94a can be the axially most forward of the two lateral insert extensions 98a, 98b with respect to the longitudinal direction of the cutting insert 24. Advantageously, this allows face milling since the short insert lateral extension 98b of the non-active cutting portion 94b does not interfere with the workpiece. When a double-ended cutting insert 24 is retained in an insert receiving slot 38, the wide lateral extension 98a belonging to the non-active cutting portion 94b located in the radially inner portion of the insert receiving slot 38 protrudes in the recess of front shank 60. Thus, a front shank indentation function 60 is to accommodate and thus provide looseness for the inactive side extension 98a.

[076] The insert end surface 90 opposite the cutting portion 94a includes an indented insert portion 100 having an insert key surface 102, configured for support with the offset pin 51a of key 52 used to extract the insert from cut 24 of the insert receiving slot 38. The insert key surface 102 is closer to the lower insert surface 86 than the upper insert surface 84. According to some embodiments of the subject matter of the present application, the key surface insert 102 can be located entirely below the median plane of insert M. In a side view of the cutting insert 24, perpendicular to the longitudinal axis of insert A (i.e., Fig. 8), the insert key surface 102 can be concavely curved. It is understood that a side view of the cutting insert 24 is a view along (i.e., parallel to) the lateral axis of insert E. Preferably, the insert wrench surface 102 can be defined by a radius of wrench surface RK insert. The surface radius of the RK insert wrench can be greater than or equal to 0.6 mm and less than or equal to 1.0 mm. Such a configuration ensures a smooth transfer of the extraction forces from the displacement pin 51a to the cutting insert 24.

[077] According to some embodiments of the subject matter of the present application, the insert end surface 90 opposite the cutting portion 94a may include an insert stop surface 104, for contact with the radial slot stop surface 46. A insert stop surface 104 may be closer to the upper insert surface 86 than to the lower insert surface 86. Insert stop surface 104 may be flat. It is understood that in a double-ended cutting insert, as seen in the figures, both opposite end surfaces 90 are provided with a recessed portion 100 having a key surface 102 and a stop surface 104.

[078] In the assembled state of the rotary slit cutting tool 20, the cutting insert 24 is releasably and resiliently secured in the insert receiving slit 38 by the resilient fastener member 34. The slotted member support surface 42 supports the upper insert bearing surface 84a. The lower jaw support surface 44 supports the lower insert support surface 86a. As is known, the slit fastening member support surface 42 and / or the slit lower jaw support surface 44 may include two or more support sub-surfaces spaced apart from each other and thus each of them may not literally be a single support surface. In this non-limiting example shown in the drawings (for example, Fig. 5), the lower jaw support surface 44 includes two longitudinally spaced support sub-surfaces. The radial slot stop surface 46 supports the insert stop surface 104.

[079] To extract the cutting insert 24 from the insert receiving slot 38 the key 52 can be used. The key 52 has two pins, the displacement pin 51a and the pivot pin 51b. Simultaneously, the displacement pin 51a is inserted into the screwdriver portion 50 and the pivot pin 51b is inserted into the pivot pin hole 31. The key 52 is then pivoted over the pivot pin 51b so that the displacement pin 51a incites the cutting insert 24 out of the insert receiving slot 38, along the insert receiving slot axis C.

[080] It is noted that, due to the insert receiving slot deviated inward 38, the cutter portion diameter DC can be reduced without the need to also reduce the stem portion diameter DS. This is advantageous for making internal splitting in a small hole. For example, for a DC cutter portion diameter of less than 30 mm, the DC cutter portion diameter may be less than twice the DS stem portion diameter. In particular, in a configuration having exactly three fastener portions 32, exactly three front shank indentations 60 and exactly three non-indented front shank portions 62, the diameter of the DC cutter portion can be less than or equal to 20 mm. In such tools, the cutting insert 24 is correspondingly sized. For example, the insert length can be between 6 mm and 7 mm, the insert width can be between 1.5 mm and 2.5 mm and the insert height can be between 2 mm and 3 mm.

[081] It is further noted that, due to the insert receiving slot 38 being deflected inwardly, the cooling channel outlet 82 is located in the vicinity of the cutting edge 96 of the active cutting portion 94a.

[082] It should also be noted that, due to the cutting insert 24 being resiliently secured in the insert receiving slot 38, the cutting insert 24 can be devoid of a through hole for a retaining screw. Note also that by virtue of the placement of the insert key surface 102 on the recessed insert portion 100 of the insert end surface 90, the size of the screw driver portion 50 of any insertion receiving slot 38 may be reduced. This is advantageous in small diameter tools where otherwise the screwdriver portion 50 would be close enough to the adjacent fastener portions 32 to adversely affect its fastening abilities.

[083] Although the subject matter of the present application has been described with a certain degree of particularity, it should be understood that various changes and modifications can be made without departing from the spirit or scope of the invention, as claimed hereinafter.

Claims (27)

1. Slit tool body (22), characterized by the fact that it has a central axis of the body (B) that defines opposite directions forwards and backwards (Dr, Dr) and on which the slit tool body (22) is rotatable in a rotational direction (R), the slit tool body (22) comprising: a disk-type cutter portion (26) comprising a resilient clamping portion (32) having a peripherally arranged insert receiving slot (38); and a stem portion (56) projecting backwards from the cutter portion (26), the stem portion (56) comprising a peripheral stem surface (58) which extends circumferentially over the central axis of the body (B) and a front shank indentation (60) indented in and opened outwardly to the peripheral shank surface (58) adjacent the cutter portion (26); wherein: a portion radially into the insert receiving slot (38) merges in the backward direction (Dx) with the indentation of the front shank (60). 2. Slit tool body (22) according to claim 1, characterized in that the cutter portion (26) and the shank portion (56) are integrally formed so that the slit tool body (22) has a unitary, one-piece construction. Slit tool body (22) according to claim 1 or 2, characterized in that the gripping portion (32) further comprises a resilient gripping member (34) and a lower jaw member (36) oppose each other and are separated from each other by the insert receiving slot (38), the resilient fastening member (34) being rotatably arranged in front of the lower jaw member (36) and configured to resiliently hold a cutting insert (24 ) in the insert receiving slot (38). 4, Slit tool body (22) according to claim 3, characterized in that the resilient fastening member (34) is axially adjacent to the front shank indentation (60). Slit tool body (22) according to claim 3 or 4, characterized in that the stem portion (56) comprises a non-recessed front stem portion arranged peripherally (62) that is circumferentially adjacent to the front shank (60) and axially adjacent the cutter portion (26). 6. Slit tool body (22) according to claim 5, characterized in that: the cutter portion (26) further comprises at least one additional resilient clamping portion (32) to form a plurality of clamping portions (32) which are angularly spaced from each other; the stem portion (56) additionally comprises at least one additional front stem indentation (60) to form a plurality of front stem indentations (60) that are angularly spaced from each other; the stem portion (56) further comprises at least one additional non-recessed front stem portion (62) to form a plurality of non-recessed front stem portions (62) that are angularly spaced from each other, each front stem portion not recessed (62) being located between two circumferentially adjacent front rod indentations (60); and a portion radially inward of each insert receiving slot (38) merges in the backward direction (Dr) with the respective front stem indentation (60). 7. Slit tool body (22) according to claim 5 or 6, characterized in that, in a direction along the central axis of the body (B); an imaginary radius line that extends between the central axis of the body (B) and a more distant portion in the non-receding front stem portion (62) defines a stem portion radius (RS) of a stem portion circle ( CS) which is centered on the central axis of the body (B) and which has a stem portion diameter (DS); and the cutter portion (26) defines a circumscribed cutter portion circle (CC) that is centered on the central axis of the body (B) and that has a cutter portion diameter (DC). 8. Slit tool body (22) according to claim 7, characterized in that in a direction along the central axis of the body (B), the stem portion circle (CS) intersects the slit of insert reception (38). Slit tool body (22) according to claim 7 or 8, characterized in that: the insert receiving slot (38) is defined by an elongated slit peripheral surface (40) comprising a surface slit lower jaw support (44) located on the lower jaw member (36); and in a direction along the central axis of the body (B), the stem portion circle (CS) intersects the lower slit jaw support surface (44). Slit tool body (22) according to claim 9, characterized by the fact that: the peripheral slit surface (40) further comprises a slit fastening member support surface (42) located on the fastening member resilient (34); and in a direction along the central axis of the body (B), the slit fastening member support surface (42) is located radially outside the stem portion circle (CS). 11. Slit tool body (22) according to claim 10, characterized by the fact that: the peripheral slit surface (40) further comprises a radial slit stop surface (46) located circumferentially between the surface of slit fastening member support (42) and the slit lower jaw support surface (44); and in a direction along the central axis of the body (B), the radial slot stop surface (46) is located radially within the stem portion circle (CS). Slit tool body (22) according to any one of claims 1 to 11, characterized in that the front shank indentation (60) comprises an outer peripherally arranged indentation gap (64) defined by a surface with an external forward-facing recoil base (66) and an external peripheral recoil surface (68) extending transversely thereto, the external recoil base surface (66) and each end of the external recoil outer surface (68) ) intersecting the peripheral stem surface (58). 13. Slit tool body (22) according to claim 12, characterized in that: the front stem indentation (60) additionally comprises an internal indentation gap (74) defined by an internal base surface of forward recoil (76) and an internal peripheral recoil surface (78) extending transversely thereto; the internal recessed base surface (76) intersects the external peripheral recessed surface (68); and each end of the internal peripheral recoil surface (78) intersects the external peripheral recoil surface (68). Slit tool body (22) according to claim 12 or 13, characterized in that the external recess gap (64) is formed by a circumferential groove extending in the circumferential direction. Slit tool body (22) according to claim 14, characterized in that in a direction along the central axis of the body (B), the outer peripheral recoil surface (68) is curved in a way concave and defined by an external peripheral recoil radius (RO). 16. Slit tool body (22) according to any one of claims 12 to 15, characterized in that, in a side view of the slit tool body (22), the outer peripheral recoil surface (68 ) is concavely curved and defined by a peripheral lateral radius (RS). 17. Rotating slit cutting tool (20), characterized in that it comprises: a slit tool body (22) as defined in any one of claims 1 to 16; and a cutting insert (24), loosely and resiliently attached to the insert receiving slot (38). 18. Rotating slit cutting tool (20) according to claim 17, characterized by the fact that: the cutting insert (24) is longitudinally elongated in a direction defining a longitudinal axis of the insert (A), the cutting insert (24) comprising: upper and lower surfaces of opposite inserts (84, 86) and a peripheral surface of insert (88) extending between them, the peripheral insert surface (88) comprising two opposite insert end surfaces (90) connecting the top and bottom insert surfaces (84, 86) and two opposite insert side surfaces ( 92) which also connect the upper and lower insert surfaces (84, 86); a longitudinal insert plane (P1) containing the longitudinal insert axis (A), passing between the lateral insert surfaces (92) and intersecting the upper and lower insert surfaces (84, 86) and also intersecting the end surfaces of opposite insert (90); and a cutting portion (94a) located at one cutting insert end (24), the cutting portion (94a) comprising a cutting edge (96) formed at the intersection of the upper insert surface (84) and one of the two insert end surfaces (90); wherein: the insert end surface (90) opposite the cutting portion (94a) comprises an indented insert portion (100) comprising an insert key surface (102) which is closest to the lower insert surface (86) ) than the top insert surface (84), the insert key surface (102) being configured for support by a displacement pin (51b) of a key (52) used to extract the cutting insert (24) from from the insert receiving slot (38). 19. Rotary screw cutting tool (20) according to claim 18, characterized in that in a side view of the cutting insert (24), the surface of the insert wrench (102) is concavely curved . 20. Rotary slit cutting tool (20) according to claim 18 or 19, characterized in that the insert wrench surface (102) is located entirely below a median plane of insert (M) extends halfway between the upper and lower insert surfaces (84, 86) and contains the longitudinal insert axis (A). 21. Rotary slit cutting tool (20) according to any one of claims 18 to 20, characterized in that the insert end surface (90) opposite the cutting portion (94a) further comprises a surface of insert stop (104) which is closer to the upper insert surface (84) than to the lower insert surface (86), the insert stop surface (104) being flat. 22. Rotary slit cutting tool (20) according to any one of claims 18 to 21, characterized in that: the cutting insert (24) comprises an additional cutting portion (94a) forming two cutting portions (94a, 94b), the two cutting portions (94a, 94b) being formed at the opposite ends of the cutting insert (24). 23. Rotary slit cutting tool (20) according to claim 22, characterized in that: each insert cutting portion (94a, 94b) comprises two lateral insert extensions (98a, 98b) which they project laterally from opposite sides of the cutting insert (24) in a direction away from the longitudinal plane of the insert (P1) and over which the cutting edge (96) extends; the two lateral insert extensions (98a, 98b) comprise a wide and a narrow insert extension (98a, 98b), the wide insert lateral extension (98a) being longer than the narrow insert lateral extension (98b) in a direction perpendicular to the longitudinal plane of the insert (P1); and the wide lateral insert extensions (98a) are located on opposite sides of the longitudinal insert plane (P1). 24. Rotary slit cutting tool (20) according to claim 23, characterized in that: the two cutting portions (94a, 94b) comprise an active cutting portion (94a) and a non-cutting portion active (94b), the cutting edge (96) of the active cutting portion (94a) being located beyond the radial extension of the cutter portion (26); and the wide lateral insert extension (98a) of the active cutting portion (94a) is axially ahead of the two lateral insert extensions (98a, 98b) in relation to the axial direction. 25. Rotating slit cutting tool (20) according to any one of claims 17 to 24, characterized in that the insert receiving slot (38) comprises a slot insert portion (48) defined by a insert profile (IP) of cutting insert (24) in a direction along the central axis of the body (B); and a portion radially inward of the slot insert portion (48) merges in the backward direction (Drg) with the front stem indentation (60). 26. Cutting insert (24), characterized by the fact that it is longitudinally elongated in a direction that defines a longitudinal axis of the insert (A), comprising: upper and lower surfaces of opposite inserts (84, 86) and a peripheral surface of insert (88) extending between them, the peripheral insert surface (88) comprising two opposite insert end surfaces (90) connecting the top and bottom insert surfaces (84, 86) and two opposite insert side surfaces ( 92) which also connect the upper and lower insert surfaces (84, 86); a longitudinal insert plane (P1) containing the longitudinal insert axis (A), passing between the lateral insert surfaces (92) and intersecting the upper and lower insert surfaces (84, 86) and also intersecting the end surfaces of opposite insert (90); and two cutting portions (94a, 94b) located at opposite ends of the cutting insert (24), each comprising a cutting edge (96) formed at the intersection of the upper insert surface (84) and one of the two end surfaces insert (90); where: each insert cut portion (94a, 94b) comprises two lateral insert extensions (98a, 98b) which project laterally from opposite sides of the cut insert (24) in a direction away from the longitudinal plane of insert (P1) and over which the cutting edge (96) extends; the two lateral insert extensions (98a, 98b) comprise a wide and narrow lateral extension extension (98a, 98b), the wide insert lateral extension (98a) being longer than the narrow insert lateral extension (98b) in one direction perpendicular to the longitudinal plane of the insert (P1); and the wide lateral insert extensions (98a) are on opposite sides of the longitudinal insert plane (P1). 27. Slit tool body (22), characterized by the fact that it has a central axis of the body (B) that defines opposite directions forwards and backwards (Dr, Dr) and on which the slit tool body (22) is rotatable in a rotational direction (R), the slit tool body (22) comprising: a disk-type cutter portion (26) comprising a resilient clamping portion (32) having a peripherally arranged insert receiving slot (38); and a stem portion (56) projecting backwards from the cutter portion (26), the stem portion (56) comprising a peripheral stem surface (58) which extends circumferentially over the central axis of the body (B) and a front shank indentation (60) indented in and opened outwardly to the peripheral shank surface (58) adjacent the cutter portion (26); on what: in a front view of the slit tool body (22), in a direction along the central axis of the body (B), the shank portion (56) is partially visible through the insert receiving slot (38).